Effect of temperature, salt stress and pH on seed germination of medicinal plant Origanum compactum

•No published study has investigated the effect of abiotic factors on O. compactum seed germination.•Temperature range between 10 and 15 °C is more suitable for germination of O. compactum seeds.•Salt stress had a negative effect on the seed germination of O. compactum.•The pH 7 is qualified as the optimal pH of germination.

The aim of this study was to evaluate the impact of temperature, salt stress and pH on seed germination of a Moroccan medicinal plant Origanum compactum (Benth). Mature seeds were isolated from O. compactum collected from two areas belonging to Ouezzane province at post-flowering stage. The in vitro seed germination tests were carried out in the dark in Petri dishes using an aqueous media. The influence of temperature, salt stress and pH was evaluated by following the evolution of germination over time. The results showed an optimal temperature of 15 °C with a maximal germination percentage of 81%, an optimum pH equal to 7 with 71% as a maximal germination percentage and a negative correlation between NaCl concentration and seed germination. The seed germination was null at high temperature (25 °C) and at high NaCl concentration (>7.5 g/l) as well as at acid pH (pH <3.5). These data may serve as guidelines for species-specific propagation protocols, and ex situ conservation.